As a rough guide, for any international launches in USD, I multiply it by 100 (not 75) to get an idea for actual Indian price (gst, imports, any extras). Always changing or arbitrary % for imports, gst etc make it impossible to price at exchange rate(not that I am expecting at that rate). x100 seems to be working fine for guesses.
3070
499USD x100 = 49900 (Actual 51000)
3080
699USD x100 = 69900 (Actual 71000)
3090
1499USD x100 = 149900 (Actual 152000)